Valve lifter



May 2o, 1941.

J. NAAB 2,242,367

VALVE LIFTER Filed Feb. 2', 1959 HIS ATTORNEY Patented May 20, 1941 sPeli VALVE LIFTER Julius Naab, Easton, Pa., assignor to Ingersoll- RandCompany, Jersey City, N. J., a corporation of New Jersey 2 Claims.

This invention relates to compressors, and more particularly to a valvelifter for controlling the loaded and unloaded periods of a compressor.

One object of the invention is to assure against leakage of pressurefluid through the valve lifter to the atmosphere.

Another object is-to enable the power device of the valve lifter to beserviced at any time, irrespective of whether the compressor is inoperation or idle.

A further object is to eliminate the necessity of frequent inspectionsand replacements of the parts comprising the power element of the valvelifter.

Other objects will be in part obvious and in part pointed outhereinafter.

In the drawing accompanying this speciiication and in which similarreference numerals refer to similar parts,

Figure l is an elevation, in section, of a valve lifter constructed inaccordance with the prac- `tice of the invention and a compressor inletvalve to which it is applied, and

Figure 2 is an elevation, in section of a modified form of theinvention.

Referring more particularly to the drawing, designates a portion of acompressor casing and 2| a valve assembly which controlsthe admission offluid from a channel 22 into a compression chamber 23 in the casing 20.

The valve assembly 2| is shown as being of a conventional typecomprising a stop plate 24 seated in an inner wall 25 of the casing 2|)and having ports 26 for the passage of the fluid into the compressionchamber 23. A valve seat 21 rests upon the stop plate 24 and likewisehas ports 28 which are controlled by spring-pressed valves 29 foradmitting fluid from the channel 22 into the compression chamber 23.

T-he valve seat 21 supports a sleeve 30 which extends into a bore 3| inan outer wall 32 of the casing 20 and has ports 33 to affordcommunication between the channel 22 and the interior of the sleeve. Thesleeve 30 is secured to the valve seat by bolts 34 and has an internalflange 35 in its outer end from which depends an integral annular wall36.

The interior or opening 31 of the wall 36 also extends through theflange 35 and serves as a guide for a valve lifter 3B whereby the valves29 are unseated to permit of uninterrupted communication between thecompression chamber 23 and the channel 22 whenever conditions in thecompressing system require the unloading of the compressor. The valvelifter 38 comprises,

inthe present instance, a piston portion 33 which is slidable in theopening 31 and has a flange 49 the outer surface 4| of which cooperateswith the adjacent end 42 of the wall 36 to normally prevent the passageof ud through the opening 31. Fingers 43 on the flange lil extend intothe ports 28 and terminate a slight. distance above the valvesv 29 sothat they will be out of contact Ywith the valves during the normaloperation of the compressor. v

The piston 39 is hollow and its outer end wall 44 serves as a seat foran end'oi a spring 45 seated upon the valve seat 21 to urge the valvelifter 38 outwardly and to maintain the flange 40 in engagement with thesurface 42 of the annular wall 36.

The mechanism that supplies the powerl required for actuating the Valvelifter 38 is arranged coaxially with the valve assembly 2|. It comprisesa casing 46 having a skirt 41 extending into the bore 3|. On theperiphery of the casing |56 is a liange 48 through which extend bolts 49that are threaded into the wall 32 of the compressor casing to maintainthe skirt 41 in the bore 3|.

The casing 46 is hollow throughout, having an opening 5U into the innerend of which eX- tends a plunger 5| which preferably fits loosely in theopening 56 and has a stem 52 terminating in a foot-piece 53 to engagethe end of the piston 39. At the inner end of the plunger is an externalflange 54 to engage the adjacent end 55 of the casing 46 for preventingthe passage of fluid along the peripheral surface of the plunger andthus through the casing.

In the outermost end of the plunger 5I is a concavity 56 to receive aflexible sack 51, preferably of rubber, which lies in the outer end ofthe opening 50 to serve as a receptacle for pressure fluid employed foractuating the plunger 5|. At the mouth of the sack 51 are lateral innerand outer flanges 58 and 59, respectively, and the latter ange seatsupon the outer end of the casing 46 and is clamped thereagainst by aplate 60 that serves as a cover for the casing 46.

The flange 58 also seats against the plate 69 and is preferably providedwith annular ribs 6| that extend into grooves 62 in the inner surface ofthe plate 60 to 4further preclude leakage of fluid between thecooperating surfaces of the flange 58 and the plate 69. The ribs 6| areheld firmly in engagement with the grooves 62 by a plate 63 having ahollow stem 64 projecting through the plate 66 for introducing pressureuid into the sack 51. A nut 65 threaded 0n the stem 64 seats against theouter surface of the plate 60 to press the plate 63 against the ilange58.

To the end that the sack 51 may be fully capable of withstanding theflexion to which it will be subjected in operation, the annular portion66 adjoining the flanges 58 and 59 and lying directly in the mouth ofthe opening 50 is of materially greater thickness than the remainingportions of the sack and, in order that the sack proper may be readilyresponsive to the pressureof the iluid introduced thereinto, the bodypori tion of the sack is of gradually decreasing thickness from theannular portion 66 to the central bottom part 61 of the sack.

In the assembled position ofthe cage 48 they skirt 41 is spaced a slightdistance from the adjacent end of the sleeve 33. This spacing of theskirt may vary, as required, to assure the.

lagainst the ange 59. The bolts 10 thus serve to secure the plate 60 tothe cage 46 and also to clamp the valve assembly securely in position inthe compressor.

In practice, during the time the pressure value of the fluid in thecompressing system is below -the predetermined .maximum value intendedto be maintained in the system the valve lifter 38 occupies theretracted position in which the ngers 43 are out of `engagement with thevalves 29. The valve lifter will be held in this position by the spring45 which will also supply the force for norm-ally pressing the flange 54against the end surface 55 of the cage. Owing to this `arrangement theinner end of the lopening 50 will be sealed and the sack 51 may beuncovered for inspection, or such other attentions which it may require,without stopping the compressor.

The parts comprising the valve lifter will remain in the .positionsdescribed until the pressure uid in the compressing system attains themaximum predetermined value. Pressure fluid is then admitted into thesack 51, by suitable devices (not shown), and will actuate the plunger5I towards the valves. This movement of the plunger will cause the ngers43 to unseat the valves 29 and thereby communicate the compressionchamber 23 with Ithe channel 22. The valves will remain unseated untilfthe pressure of the uid in the compressing system again falls to apredetermined low value. The devices controlling the pressure iluidsupply to the sack will then operate to deate the sack, whereupon thespring will actuate the valve lifter 38 rto release the valves 29 and.the load will then again be applied to the compressor.

In the modied form of the invention shown in Figure 2, the sack,designated by 12, carries onlythe flange 59 which is clamped between the.plate 60 and the cagek46 by the bolts 10 and nuts 1 I. f The annularpontion 66 and the body portion of the sack are identical with thecorresponding portions of the sack shown in Figure 1, and a conduit 13is threaded .to the plate 60 and communicates with the interior of thesack through a port 14 in the plate for conveying pressure uid to andfrom the sack for operating the plunger.

2. An actuator, comprising a casing, a iiexiblev sack in the casing,inwardly and outwardly extending Ilanges at the mouth of and integralwith the sack, a member rto press the outwardly extending flange againstthecasing, means for clamping the inwardly extending Iiange against themember, and interlocking portions on fthe `member and the inwardlyextending flange for lpreventing relatively lateral movement betweensaid member and the inwardly extending ange.

. JULIUS NAAB.

